Infertility, defined as inability to conceive within one year of intercourse without contraception, is a common health condition for couples. Infertility treatments range from less invasive medical treatments (including ovulation induction and artificial insemination) to assisted reproductive technologies (ART), which complete early stages of human reproduction in vitro. ART produces high pregnancy rates in the short term, making it an attractive treatment. However, epidemiologic studies have demonstrated higher incidence of preterm birth, low birth weight, and birth defects among children conceived through ART, when compared to children conceived naturally, even when the analyses are limited to singleton pregnancies. Major questions remain as to whether these adverse outcomes are related to the treatments or to the underlying causes of the infertility. Because most data on infertility treatments and outcomes are clinic-based rather than population-based, it has been difficult to address such questions. This study will address these issues in couples that receive a variety of treatments. We propose to conduct a pilot retrospective observational study in a clinic-based and a parallel population-based cohort of women under age 35 with male partners and primary infertility. The study will include questionnaire design and piloting, data linkage, participant recruitment, and data collection through record reviews and surveys of women about their treatments and pregnancies. Outcomes include cumulative probabilities of live birth, time to live birth, preterm birth, low birth weight, multiple gestation, birth defects, and neonatal morbidity. To assemble a clinic-based cohort, we will use clinical treatment records from the Utah Center for Reproductive Medicine (UCRM) to identify potential participants. To establish a parallel population- based cohort, we will use marriage certificates, birth certificates, and fetal death certificates from the UPDB to identify potential participants. For both cohorts, we will establish final eligibility by telephone screening. Upon contact, final eligibility, and consent, women in both cohorts will be asked to complete a questionnaire to collect and verify information on infertility treatment choices and time attempting pregnancy. To ascertain birth outcomes, we will link the individual records from both cohorts to two sources: Utah state birth certificates data via the Utah Population Database (UPDB) and birth defects data via the active surveillance of the Utah Birth Defects Network (UBDN). Ultimately, we expect that approximately 1000 women will participate in the study, with 500 from each cohort, yielding approximately 130 women (with an estimated 65 live births) who have received ART, 520 women (with an estimated 234 live births) who have received less-invasive infertility treatment, and 350 women (with an estimated 88 live births) who have received no treatment. This will give us power to look at cumulative pregnancy probabilities and common birth outcomes;and the opportunity to explore other outcomes. The results of this study will describe clinically relevant outcomes for couples seeking to have healthy children and will also inform the development of future targeted randomized trials. PUBLIC HEALTH RELEVANCE: Infertility is an important public health issue because it impacts millions of couples in the United States and other countries, and there are growing concerns about poor perinatal outcomes associated with some types of infertility treatment. We propose a pilot retrospective observational study in a clinic-based cohort and parallel population-based cohort of women under age 35 with primary infertility to study the cumulative probabilities of live birth, time to live birth, preterm birth, low birth weight, birth defects, and neonatal morbidity associated with different types of infertility treatment. The results of this study will describe clinically relevant outcomes for couples seeking to have healthy children and will also inform the development of future targeted randomized trials.